Apparatus for Plasma Processing

ABSTRACT

According to an embodiment, an apparatus for a plasma processing system is provided. The apparatus includes an interface, a radiating structure, and conductive offsets. The interface includes a first conductive plate couplable to an RF source, a second conductive plate disposed between the RF source and the first conductive plate, and conductive concentric ring structures disposed between the second conductive plate and a substrate holder. The conductive offsets are arranged to couple the conductive concentric ring structures to the radiating structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/235,418, filed on Aug. 20, 2021, which application is incorporated by reference herein in its entirety. This application further claims the benefit of U.S. application Ser. No. 17/649,823, filed on Feb. 3, 2022, and Ser. No. 17/748,737 filed on May 19, 2022, which applications are incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present disclosure generally relates to semiconductor processing technology and, in particular embodiments, to an apparatus radiating electromagnetic waves in a plasma processing system for treating a substrate therein.

BACKGROUND

Plasma processing is extensively used in the manufacturing and fabrication of high-density microscopic circuits within the semiconductor industry.

In a plasma processing system, an electromagnetic wave radiated into a plasma chamber generates an electromagnetic field. The generated electromagnetic field heats electrons in the chamber. The heated electrons ignite plasma that treats the substrate in a process such as for etching, deposit, oxidation, sputtering, or the like.

A non-uniform electromagnetic field within the plasma processing chamber results in a non-uniform treatment of the substrate due to different portions of the substrate being treated with varying densities of plasma. An apparatus and system that improves the uniformity of the electromagnetic field in a plasma processing system are, thus, desirable.

SUMMARY

A first aspect relates to an apparatus for a plasma processing system. The apparatus includes an interface, a radiating structure, and conductive offsets. The interface includes a first conductive plate couplable to an RF source, a second conductive plate disposed between the RF source and the first conductive plate, and conductive concentric ring structures disposed between the second conductive plate and a substrate holder. The conductive offsets are arranged to couple the conductive concentric ring structures to the radiating structure.

In a first implementation form of the apparatus according to the first aspect as such, the second conductive plate is grounded.

In a second implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the radiating structure includes a third conductive plate with a plurality of axisymmetric spiral cutouts.

In a third implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the plasma processing system includes a processing chamber having a substrate holder. A substrate is mounted on the substrate holder to be processed in the processing chamber.

In a fourth implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the apparatus is disposed external to the processing chamber.

In a fifth implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the first conductive plate is coupled to the RF source via a coaxial conductive structure, and the RF source feeds RF power to first conductive plate via the coaxial conductive structure.

In a sixth implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the apparatus further includes non-conductive offsets, and the radiating structure is coupled to an insulating structure disposed between a conductive inner ring structure of the conductive concentric ring structures and a conductive outer ring structure of the conductive concentric ring structures by the non-conductive offsets.

In a seventh implementation form of the apparatus according to the first aspect as such or any preceding implementation form of the first aspect, the interface, the radiating structure, and the conductive offsets form a resonant circuit in response to the RF source providing an RF power to the first conductive plate.

A second aspect relates to an apparatus for a plasma processing system. The apparatus includes an interface and a radiating structure coupled to the interface. The interface includes a first conductive structure couplable to an RF source, a second conductive structure disposed between the RF source and the first conductive structure, and concentric conductive structures. Each concentric conductive structure is isolated from the second conductive structure by an air gap.

In a first implementation form of the apparatus according to the second aspect as such, each concentric conductive structure is isolated from an adjacent concentric conductive structure by the air gap.

In a second implementation form of the apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the apparatus further includes conductive offsets coupling the concentric conductive structures to the radiating structure.

In a third implementation form of the apparatus according to the second aspect as such or any preceding implementation form of the second aspect, a resonant frequency of the radiating structure is between 5 and 100 megahertz (MHz).

In a fourth implementation form of the apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the radiating structure includes a conductive plate having spiral cutouts, and an inner circular cutout. The first conductive structure is arranged substantially on a same plane as the radiating structure and positioned inside the inner circulator cutout.

In a fifth implementation form of the apparatus according to the second aspect as such or any preceding implementation form of the second aspect, the plasma processing system includes a processing chamber having a substrate holder. The substrate to be processed in the processing chamber is mounted on the substrate holder.

A third aspect relates to an antenna system for exciting plasma by inductive coupling. The antenna system includes a plate, a conductive ring structure, conductive offsets, and a plurality of spiral arms. The conductive ring structure is arranged in parallel to the plate. The plate and the conductive ring structure form a first capacitor, and the capacitance value of the first capacitor is substantially the same along one conductive ring structure. Each conductive offset includes a first end and a second end, where a first end of each conductive offset is coupled to the conductive ring structure in a perpendicular arrangement. Each conductive offset is arranged equal distance from other conductive offsets along the conductive ring structure. The plurality of spiral arms are coupled to a corresponding second end of each conductive offset. Each spiral arm is arranged in a radial, azimuthal, and nested arrangement. Each spiral arm has the same shape, length, and spacing. The plurality of spiral arms, conductive offsets, and the conductive ring structure form a resonant structure that resonates at an RF frequency.

In a first implementation form of the antenna system according to the third aspect as such, the antenna system further includes at least one drive conductive structure capacitively coupled to the resonant structure and couplable to an RF source.

In a second implementation form of the antenna system according to the third aspect as such or any preceding implementation form of the third aspect, the antenna system further includes a conductive coil structure inductively coupled to the resonant structure. The conductive coil structure and the resonant structure form an inductively coupled pair. The conductive coil structure being couplable to an RF source.

In a third implementation form of the antenna system according to the third aspect as such or any preceding implementation form of the third aspect, the conductive ring structure includes a conductive inner ring structure and a conductive outer ring structure adjacent to the conductive inner ring structure. Each of the conductive inner ring structure and the conductive outer ring structure are coupled to the plurality of spiral arms by the conductive offsets.

In a fourth implementation form of the antenna system according to the third aspect as such or any preceding implementation form of the third aspect, one of an inner or an outer edge of each of the plurality of spiral arms is connected to the conductive ring structure by the conductive offsets, and another edge of the each of the plurality of spiral arms is not directly connected to a conductive structure or ground.

In a fifth implementation form of the antenna system according to the third aspect as such or any preceding implementation form of the third aspect, the plurality of spiral arms, the plate, and the conductive ring structure are arranged substantially parallel to each other.

Embodiments can be implemented in hardware, software, or in any combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram of an embodiment plasma processing system;

FIG. 2A is a side view of an embodiment resonating structure;

FIG. 2B is a schematic of the embodiment resonating structure of FIG. 2A;

FIG. 2C is a flowchart of an embodiment method, as may be performed by the embodiment resonating structure of FIG. 2A;

FIG. 3A is a side view of another embodiment resonating structure;

FIG. 3B is a schematic of the embodiment resonating structure of FIG. 3A;

FIG. 3C is a flowchart of an embodiment method, as may be performed by the embodiment resonating structure of FIG. 3A;

FIG. 4A is a side view of another embodiment resonating structure;

FIG. 4B is a schematic of the embodiment resonating structure of FIG. 4A;

FIG. 4C is a flowchart of an embodiment method, as may be performed by the embodiment resonating structure of FIG. 4A;

FIG. 5A is a side view of another embodiment resonating structure;

FIG. 5B is a schematic of the embodiment resonating structure of FIG. 5A;

FIG. 5C is a flowchart of an embodiment method, as may be performed by the embodiment resonating structure of FIG. 5A;

FIG. 6A is a side view of another embodiment resonating structure;

FIG. 6B is a schematic of the embodiment resonating structure of FIG. 6A;

FIG. 6C is a flowchart of an embodiment method, as may be performed by the embodiment resonating structure of FIG. 6A;

FIG. 7A is a side view of another embodiment resonating structure;

FIG. 7B is an embodiment loop structure, which may be arranged in the resonating structure of FIG. 7A;

FIG. 7C is a schematic of the embodiment resonating structure of FIG. 7A;

FIG. 7D is a flowchart of an embodiment method, as may be performed by the embodiment resonating structure of FIG. 7A;

FIG. 8A is a side view of another embodiment resonating structure;

FIG. 8B is a schematic of the embodiment resonating structure of FIG. 8A;

FIG. 8C is a flowchart of an embodiment method, as may be performed by the embodiment resonating structure of FIG. 8A;

FIG. 9A is a side view of another embodiment resonating structure;

FIG. 9B is a schematic of the embodiment resonating structure of FIG. 9A;

FIG. 9C is a flowchart of an embodiment method, as may be performed by the resonant circuit of the resonating structure of FIG. 9A;

FIG. 10A is a side view of another embodiment resonating structure;

FIG. 10B is a schematic of the embodiment resonating structure of FIG. 10A;

FIG. 10C is a flowchart of an embodiment method, as may be performed by the resonant circuit of the resonating structure of FIG. 10A;

FIG. 11A is a side view of another embodiment resonating structure;

FIG. 11B is a schematic of the embodiment resonating structure of FIG. 11A;

FIG. 11C is a flowchart of an embodiment method, as may be performed by the resonant circuit of the resonating structure of FIG. 11A;

FIG. 12 is a top view of an embodiment radiating structure; and

FIG. 13A is a side view of another embodiment resonating structure;

FIG. 13B is a schematic of the embodiment resonating structure of FIG. 13A;

FIG. 13C is a flowchart of an embodiment method, as may be performed by an inner resonant circuit of the resonating structure of FIG. 13A;

FIG. 13D is a flowchart of an embodiment method, as may be performed by an outer resonant circuit of the resonating structure of FIG. 13A; and

FIG. 14 is a top view of another embodiment radiating structure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

This disclosure provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The particular embodiments are merely illustrative of specific configurations and do not limit the scope of the claimed embodiments. Features from different embodiments may be combined to form further embodiments unless noted otherwise.

Variations or modifications described to one of the embodiments may also apply to other embodiments. Further, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of this disclosure as defined by the appended claims.

While inventive aspects are described primarily in the context of resonating structures in a plasma processing system, the inventive aspects may be similarly applicable to fields outside the semiconductor industry. Plasma can be used to treat and modify surface properties through functional group addition. For example, to treat surfaces for paint deposit, plasma can convert hydrophobic surfaces to hydrophilic surfaces. Further, the inventive aspects are not limited to plasma. For example, RF can be used to thaw out frozen food or dry out textiles, food, wood, or the like. In these various examples and across industries, a uniform oscillating magnetic field, as disclosed herein, is advantageous.

In various embodiments, a reference to magnetic fields refers to magnetic fields oscillating at some frequency, for example, at one of RF or microwave frequencies. In these embodiments, the magnetic fields do not refer to DC magnetic fields. These and other details are discussed in greater detail below.

FIG. 1 illustrates a diagram of an embodiment plasma processing system 100. Plasma processing system 100 includes an RF source 102, a resonating structure 104, a plasma chamber 106, and, optionally, a dielectric plate 114, which may (or may not) be arranged as shown in FIG. 1 . Further, plasma processing system 100 may include additional components not depicted in FIG. 1 .

In embodiments, RF source 102 includes an RF power supply, which may include a generator circuit and a matching circuit (not shown). RF source 102 is coupled to the resonating structure 104 via a power transmission line, such as a coaxial cable or the like. RF source provides forward RF waves to the resonating structure 104. Resonating structure 104 includes one or more radiating structures. The forward RF waves travel through the resonating structure 104 and are transmitted (i.e., radiated) towards plasma chamber 106.

Plasma chamber 106 includes a substrate holder 108. As shown, substrate no is placed on substrate holder 108 to be processed. Optionally, plasma chamber 106 may include a bias power supply 118 coupled to substrate holder 108. The plasma chamber 106 may also include one or more pump outlets 116 to remove by-products from plasma chamber 106 through selective control of gas flowrates within. In embodiments, pump outlets 116 are placed near (e.g., below/around the perimeter of) substrate holder 108 and substrate no.

In embodiments, resonating structure 104 is separated from plasma chamber 106 by the dielectric plate 114, which is made of a dielectric material. Dielectric plate 114 separates the low-pressure environment within plasma chamber 106 from the external atmosphere. It should be appreciated that resonating structure 104 can be placed directly adjacent to plasma chamber 106, or resonating structure 104 can be separated from plasma chamber 106 by air. In embodiments, the dielectric plate 114 is selected to minimize reflections of the RF wave from the plasma chamber 106. In other embodiments, the resonating structure 104 is embedded within the dielectric plate 114.

In embodiments, the resonating structure 104 radiates an electromagnetic field towards the plasma chamber 106, which generates in an azimuthally symmetric, high-density the plasma 112 with low capacitively coupled electric fields. In an embodiment, the resonating structure 104 includes spiral arms connected to capacitive structures that generate the azimuthal symmetry, as disclosed herein. In embodiments, the excitation frequency of the resonating structure 104 is in the radio frequency range (10-400 MHz), which is not limiting, and other frequency ranges can similarly be contemplated. For example, inventive aspects disclosed herein are equally applicable to applications in the microwave frequency range.

In embodiments, the resonating structure 104 includes resonant elements. The resonant elements can be spiral arms that are electrically connected to capacitive structures of the resonating structure 104. In embodiments, the resonant elements have the same shape and are disposed about a central axis such that there is an N-fold symmetry upon rotation, where N is an integer greater than 1. The spiral arms and the capacitive structures are resonant with electromagnetic waves fed from the RF source 102.

In embodiments, resonant elements sustain standing electromagnetic waves. The standing electromagnetic waves have regions where the electric field is high and other regions where the magnetic field is high. The regions where the magnetic fields are high consist of conductive paths. The resonant elements are placed close to and parallel to the dielectric plate 114 such that the oscillating magnetic field from the resonant elements penetrates into the plasma chamber 106. The time-varying magnetic field induces a time-varying electric field, which transfers energy to plasma electrons.

In embodiments, the resonating structure 104 includes regions where the electric field is high—located away from the dielectric plate 114. In embodiments, such regions consist of metal structures with a flat surface. In embodiments, the flat surfaces of two of the metal pieces are opposed and separated by a dielectric. The volume between the two metal pieces occupied by the dielectric is the location of the high electric fields in the respective resonant circuit of the resonating structure 104.

In other embodiments, the metal pieces may have cylindrical or other geometries. In all cases, two metal surfaces are separated by a region filled with a dielectric material, which may also be air or vacuum.

The magnetic fields in the high magnetic field elements are due to currents that flow along these elements. The electric fields in the high electric field elements are due to the presence of charge. The elements with high electric fields are connected with other such elements through the elements with high magnetic fields such that charge flows from one region of a high electric field to another region of high electric fields by a current, which produces the magnetic field in the high magnetic field elements.

In an embodiment, the high electric field elements may also be connected to each other in such a way that the electric fields in the resonating structure 104 are in phase and have the same amplitudes. However, this feature is non-limiting.

In embodiments, the high magnetic field elements and the high electric field elements are all approximately identical to each other.

In embodiments, the elements of the resonating structure 104 where the magnetic field is high and the elements of the resonating structure 104 where the electric field is high are arranged about a central axis of symmetry. In an embodiment, the central axis of symmetry is perpendicular to the dielectric plate 114. In an embodiment where the dielectric plate 114 is in the shape of a disk, the central axis of symmetry passes through the center of the disk. The elements of the resonating structure 104 are arranged such that the geometry is unchanged upon rotation of all the elements about the axis of symmetry by an angle, which is equal to 2π divided by an integer greater than 2. In an embodiment having an eight-fold symmetry arrangement, the corresponding integer is equal to 8.

In embodiments, the RF source 102 couples energy to an interface of the resonating structure 104 to generate the standing electromagnetic waves from the resonating structure 104. In embodiments, the RF source 102 is coupled to the interface via a transmission line. It is desirable that the interface maintain the same or higher symmetry as the elements of the resonating structure 104 under rotation about the axis of symmetry.

In embodiments, the interface couples energy to the portion of the resonating structure 104 where the electric field is high—capacitive coupling. In embodiments, the interface couples energy to the portion of the resonating structure 104 where the magnetic field is high— inductive coupling. In both cases, it is possible to arrange the interface such that electromagnetic fields produced by the resonating structure 104 may penetrate into the plasma chamber 106, thereby creating plasma 112 in their own right.

In an embodiment, the resonating structure 104 couples RF power from RF source 102 to the plasma chamber 106 to treat the substrate no. In particular, resonating structure 104 radiates an electromagnetic wave in response to being fed the forward RF waves from the RF source 102. The radiated electromagnetic wave penetrates from the atmospheric side (i.e., resonating structure 104 side) of the dielectric plate 114 into plasma chamber 106. The radiated electromagnetic wave generates an electromagnetic field within the plasma chamber 106. The generated electromagnetic field ignites and sustains plasma 112 by transferring energy to free electrons within the plasma chamber 106. The plasma 112 can be used to, for example, selectively etch or deposit material on substrate no.

In FIG. 1 , resonating structure 104 is shown to be external to plasma chamber 106. In embodiments, however, resonating structure 104 can be placed internal to the plasma chamber 106.

In embodiments, the operating frequency of resonating structure 104 is between 5 and wo megahertz (MHz). In embodiments, the power delivered by resonating structure 104 ranges from 10 to 5000 Watts (W)—determined by various factors such as distance from the resonating structure 104, impedance values, or the like.

FIG. 2A illustrates a side view of an embodiment resonating structure 200.

Resonating structure 200 includes an interface 206, radiating structure 222, conductive offsets 224 a-b, which may (or may not) be arranged as shown in FIG. 2 a . Further, resonating structure 200 may include additional components not depicted in FIG. 2A.

Radiating structure 222 is coupled to interface 206 by conductive offsets 224 a-b. The radiating structure 222 is coupled to the RF source 102 by a capacitive divider, as detailed hereinbelow. Details regarding the radiating structure 222 are disclosed in FIG. 12 herein below.

Additionally shown in FIG. 2A is housing 226 a-c, which surrounds the resonating structure 200. Housing 226 a-c includes a housing sidewall 226 a, a housing bottom side 226 b, and a housing top side 226 c. Each of the housing sidewall 226 a and the housing bottom side 226 b is a conductive structure. The housing top side 226 c is illustrated with a dashed line to represent an open surface of the housing 226 a-c.

The housing bottom side 226 b is electrically coupled to a common RF ground of the RF source 102. As such, the entirety of the housing 226 a-c is grounded. The housing bottom side 226 b includes an opening to couple an RF feed path from RF source 102 to the interface 206 (i.e., drive disk 202 detailed below).

In an embodiment, the housing top side 226 c is positioned adjacent to the bottom of the plasma chamber 106. In reference to FIG. 1 , the resonating structure 200 is flipped upside down, and the housing top side 226 c of resonating structure 200 is positioned such that the dielectric plate 114 is flush with the housing top side 226 c. In such an embodiment, the dielectric plate 114 is located above the radiating structure 222 in the direction of the housing top side 226 c. The resonating structure 200 generates electromagnetic waves that radiate through the dielectric plate 114 towards the plasma chamber 106 in a direction from the housing bottom side 226 b to the housing top side 226 c.

Resonating structure 200 may operate as the resonating structure 104 in the plasma processing system 100 in FIG. 1 . It is noted that the resonating structure 200 is not limited to an application in plasma processing, and other applications are contemplated. Further, the resonating structure 200 may include additional components not depicted in FIG. 2A, such as non-conductive offsets to provide extra structural rigidity to the resonating structure 200 by mechanically connecting radiating structure 222 to interface 206.

Interface 206 includes a drive disk 202, a backplate 208, an inner ring 210, an outer ring 212, and an insulating structure 214.

The drive disk 202 is a conductive, circular structure couplable to the RF source 102 and used to provide RF waves to the radiating structure 222. In embodiments, the drive disk 202 is coupled to the RF source 102 via a rigid, semi-rigid, or flexible coaxial cable. In other embodiments, the drive disk 202 is coupled to an RF or microwave generator via any one of a variety of types of transmission lines, such as a rectangular waveguide, two parallel conductive ribbons (e.g., triax) with two cylindrical conductors contained within a larger hollow cylinder, or the like.

Backplate 208 is a conductive surface arranged between RF source 102 and the drive disk 202. Backplate 208 is substantially parallel to the drive disk 202. As shown, backplate 208 is floating.

Inner ring 210 and outer ring 212 are conductive structures. As shown, the outer ring 212 is arranged adjacent to the inner ring 210 and substantially on the same plane. In embodiments, however, the outer ring 212 may be on a different plane than the inner ring 210.

The outer ring 212 and inner ring 210 are conductive, ring-shaped plates with an inner and outer radius. Outer ring 212 and inner ring 210 have the same center point as the drive disk 202. And, the inner radius of the outer ring 212 is greater than the outer radius of the inner ring 210. The inner radius of the inner ring 210 is less than the outer radius of the drive disk 202.

Because FIG. 2A illustrates a side view of the resonating structure 200, it should be appreciated that in embodiments, there is an axis of symmetry at the center of the resonating structure 200. In embodiments, the resonating structure 200 has a cylindrical structure. In these embodiments, for example, the portion of the outer ring 212 shown on the left side of the drive disk 202 and the portion of the outer ring 212 shown on the right side of the drive disk 202 are part of the same conductive ring structure. Further, similar symmetry exists with other components of the resonating structure 200 with respect to the center of the resonating structure, such as the inner ring 210, radiating structure 222, backplate 208, etc.

Insulating structure 214 consists of an electrically insulating material such as a dielectric material or the like. In embodiments, the insulating structure 214 consists of air or vacuum. The insulating structure 214 is arranged between drive disk 202 and inner ring 210, between backplate 208 and inner ring 210, between inner ring 210 and outer ring 212, and between backplate 208 and outer ring 212.

In embodiments, the interface 206 is embedded in an insulating medium, such as air or dielectric (i.e., insulating structure 214). Although the arrow designating the insulating structure 214 is shown to point to an area—more properly a volume—of the interface 206 in FIG. 2A, it should be appreciated that the arrow is meant to imply that the insulating structure 214 covers the area or volume surrounding the different conductive and non-conductive material of the resonating structure 200.

In embodiments, insulating structure 214 may include multiple insulating structures, effectively forming a single insulating structure between the various conductive components of interface 206. In other embodiments, insulating structure 214 may be a single insulating structure formed between the various conductive components of interface 206.

As shown, conductive offsets 224 a-b are arranged perpendicular to inner ring 210, outer ring 212, and radiating structure 222. However, conductive offsets 224 a-b can also be arranged to vertically connect inner ring 210 and outer ring 212 to radiating structure 222 without being perpendicular to these surfaces.

As shown, conductive offsets 224 a-b include an inner set of conductive offsets 224 a and an outer set of conductive offsets 224 b. The inner set of conductive offsets 224 a electrically couples the inner ring 210 to an inner portion of radiating structure 222. The outer set of conductive offsets 224 b electrically couple the outer ring 212 to an outer portion of radiating structure 222.

In an embodiment, an end of each of the inner set of conductive offsets 224 a is arranged at an equal distance from each other along the surface of the inner ring 210.

In an embodiment, an end of each of the outer set of conductive offsets 224 a is arranged at an equal distance from each other along the surface of the outer ring 212.

FIG. 2B illustrates a schematic 240 of the embodiment resonating structure 200 of FIG. 2A, also referred to as a double floating capacitor configuration. Schematic 240 includes RF source 102, capacitor 242, capacitor 244, capacitor 246, capacitor 248, capacitor 249, and inductor 250, which may (or may not) be arranged as shown in FIG. 2B. Here, RF source 102 is shown as an AC power supply. In embodiments, the RF source 102 is configured to provide a forward RF wave to the resonant circuit 252.

Capacitor 242 is formed by drive disk 202, insulating structure 214, and the inner ring 210. The drive disk 202 and inner ring 210 are conductive plates arranged in parallel to the other, sandwiching insulating structure 214 in-between, forming a parallel plate capacitor. The drive disk 202 is capacitively coupled to the inner ring 210, as illustrated by capacitor 242.

Capacitor 244 (i.e., inner capacitor) is formed by backplate 208, insulating structure 214, and the inner ring 210. The backplate 208 and inner ring 210 are conductive plates arranged in parallel, sandwiching insulating structure 214 in-between, forming a parallel plate capacitor. In embodiments, the capacitance value of capacitor 244 is greater than 10 picofarads (pF). The capacitance value is substantially the same at each location of the parallel plate capacitor.

Capacitor 246 (i.e., outer capacitor) is formed by backplate 208, insulating structure 214, and the outer ring 212. The backplate 208 and outer ring 212 are conductive plates arranged in parallel, sandwiching insulating structure 214 in-between, forming a parallel plate capacitor. In embodiments, the capacitance value of capacitor 246 is greater than 10 picofarads (pF). The capacitance value is substantially the same at each location of the parallel plate capacitor.

Capacitor 248 is formed by housing bottom side 226 b, insulating structure 214, and backplate 208. The housing bottom side 226 b and backplate 208 are conductive plates arranged in parallel, sandwiching insulating structure 214 in-between, forming a parallel plate capacitor.

Capacitor 249 is formed by housing bottom side 226 b, insulating structure 214, and the inner ring 210. The housing bottom side 226 b and inner ring 210 are conductive plates arranged in parallel, sandwiching insulating structure 214 in-between, forming a parallel plate capacitor.

The first node of capacitor 242 is couplable to RF source 102 via the drive disk 202. The first node of capacitor 248 is coupled to the first node of capacitor 244 and the first node of capacitor 246 via the backplate 208. The second node of capacitor 248 and the first node of capacitor 249 are coupled to the common RF ground 262 via the housing bottom side 226 b.

Inductor 250 is formed by radiating structure 222. The first node of inductor 250 is coupled to the second node of capacitor 244, the second node of capacitor 242, and the second node of capacitor 249 via the inner set of conductive offsets 224 a and the inner ring 210. The second node of inductor 250 is coupled to the second node of capacitor 246 via the outer set of conductive offsets 224 b and the outer ring 212.

In embodiments, the inductor 250 is formed by the conductive portion of the radiating structure 222 along which there is a phase shift in the propagating electromagnetic wave, consistent in sign with the phase change of an ideal lumped circuit inductor.

In embodiments, the RF source 102 is electromagnetically coupled to each of the inner ring 210 and backplate 208 via the drive disk 202.

The inductor 250, capacitor 244, and capacitor 246 form a resonant circuit 252 (i.e., LC resonant circuit). Regarding FIG. 2A, the inner ring 210, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, the outer ring 212, the backplate 208, and the insulating structure 214 form the resonant circuit 252. There is no direct current (DC) connection between any part of the resonant circuit 252 and common RF ground in this arrangement.

The various electrical and mechanical parameters of the structural components that form the inductors and capacitors of resonating structure 200 are selected such that the resonating structure 200 operates (i.e., resonates) at a desired operating frequency.

In embodiments, capacitor 244 and capacitor 246 provide a low impedance path to resonant circuit 252, and specifically, to the elements of the radiating structure 222. In embodiments, the radiating structure 222 includes multiple spiral arms (detailed in FIG. 12 below). Each spiral arm is connected to the inner ring 210 via a conductive offset of the inner set of conductive offsets 224 a on an inner end of the spiral arm, and to the outer ring 212 via a conductive offset of the outer set of conductive offsets 224 b on an outer end of the spiral arm.

The spiral arms are connected to each other through the inner ring 210 and outer ring 212. The inner ring 210 and outer ring 212 form low impedance paths at the frequencies of interest such that the voltage difference across each of the spiral arms is substantially the same. The resulting structure prevents currents from concentrating in a subset of elements of the radiating structure 222 with improved symmetry across the elements of the radiating structure 222. Thus, the arrangement prevents non-linear effects from concentrating plasma 112 under a subset of spirals.

FIG. 2C illustrates a flowchart of an embodiment method 280 as may be performed by resonating structure 200. At step 282, RF source 102 provides a forward RF wave to drive disk 202. In response, at step 284, the RF wave is transmitted from the drive disk 202 to the radiating structure 222 (i.e., inductor 250) by capacitive coupling across capacitor 242, capacitor 244, and capacitor 246.

At step 286, radiating structure 222 radiates electromagnetic waves from the resonating structure 200 to the plasma chamber 106. At step 288, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 3A illustrates a side view of an embodiment resonating structure 300.

Resonating structure 300 may operate as resonating structure 104 in the plasma processing system 100 of FIG. 1 . It is noted that resonating structure 300 is not limited to an application in plasma processing, and other applications are similarly contemplated.

Resonating structure 300 shares several features with resonating structure 200. However, in interface 306 of resonating structure 300, the backplate 208 of resonating structure 200 is merged with the housing bottom side 226 b. Thus, in contrast to resonating structure 200, where the backplate 208 is floating, in resonating structure 300, the housing bottom side 226 b (and effectively the backplate) is connected to common RF ground.

FIG. 3B illustrates a schematic 340 of the embodiment resonating structure 300 of FIG. 3A, also referred to as a double grounded capacitor configuration. Schematic 340 includes RF source 102, capacitor 242, capacitor 344, capacitor 346, and inductor 250, which may (or may not) be arranged as shown in FIG. 3B.

Capacitor 242 is formed by drive disk 202, insulating structure 314, and inner ring 210. The drive disk 202 and inner ring 210 are conductive plates arranged in parallel to the other, sandwiching insulating structure 314 in-between, forming a parallel plate capacitor. The drive disk 202 is capacitively coupled to the inner ring 210, as illustrated by capacitor 242.

Capacitor 344 (i.e., inner capacitor) is formed by housing bottom side 226 b, insulating structure 314, and the inner ring 210. The housing bottom side 226 b and inner ring 210 are conductive plates arranged in parallel, sandwiching insulating structure 314 in-between, forming a parallel plate capacitor. In embodiments, the capacitance value of capacitor 344 is greater than 10 picofarads (pF). The capacitance value is substantially the same at each location of the parallel plate capacitor.

Capacitor 346 (i.e., outer capacitor) is formed by housing bottom side 226 b, insulating structure 314, and the outer ring 212. The housing bottom side 226 b and outer ring 212 are conductive plates arranged in parallel, sandwiching insulating structure 314 in-between, forming a parallel plate capacitor. In embodiments, the capacitance value of capacitor 346 is greater than 10 picofarads (pF). The capacitance value is substantially the same at each location of the parallel plate capacitor.

The first node of capacitor 242 is couplable to RF source 102 via the drive disk 202. The first node of capacitor 344 and the first node of capacitor 346 are coupled to the common RF ground 262 via the housing bottom side 226 b.

Inductor 250 is formed by radiating structure 222. The first node of inductor 250 is coupled to the second node of capacitor 242 and the second node of capacitor 344 via the inner set of conductive offsets 224 a and the inner ring 210. The second node of inductor 250 is coupled to the second node of capacitor 346 via the outer set of conductive offsets 224 b and the outer ring 212.

In embodiments, the RF source 102 is electromagnetically coupled to the inner ring 210 via the drive disk 202.

The inductor 250, capacitor 344, and capacitor 346 form a resonant circuit 352 (i.e., LC resonant circuit). Regarding FIG. 3A, the inner ring 210, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, the outer ring 212, the housing bottom side 226 b, and the insulating structure 314 form the resonant circuit 352.

The various electrical and mechanical parameters of the structural components that form the inductors and capacitors of resonating structure 300 are selected such that the resonating structure 300 operates (i.e., resonates) at a desired operating frequency.

FIG. 3C illustrates a flowchart of an embodiment method 380 as may be performed by resonating structure 300. At step 382, RF source 102 provides a forward RF wave to drive disk 202. In response, at step 384, the RF wave is transmitted from the drive disk 202 to the radiating structure 222 (i.e., inductor 250) by capacitive coupling across capacitor 242, capacitor 344, and capacitor 346.

At step 386, radiating structure 222 radiates electromagnetic waves from the resonating structure 300 to the plasma chamber 106. At step 388, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 4A illustrates a side view of an embodiment resonating structure 400. Resonating structure 400 may operate as the resonating structure 104 in the plasma processing system 100 in FIG. 1 . It is noted that the resonating structure 400 is not limited to an application in plasma processing, and other applications are contemplated.

Resonating structure 400 shares several features with resonating structure 200. In contrast to resonating structure 200, where the insulating structure 214 is arranged between the backplate 208 and the outer ring 212 in interface 206, in resonating structure 400, the corresponding backplate 208 and outer ring 212 of resonating structure 200 are directly coupled (i.e., electrically and mechanically)—represented by backplate 408 in FIG. 4A. The outer set of conductive offsets 224 b electrically and mechanically couple the radiating structure 222 to the backplate 408.

FIG. 4B illustrates a schematic 440 of the embodiment resonating structure 400 of FIG. 4A, also referred to as a single floating capacitor configuration. Schematic 440 includes RF source 102, capacitor 442, capacitor 444, capacitor 448, capacitor 449, and inductor 250, which may (or may not) be arranged as shown in FIG. 4B.

Capacitor 442 is formed by drive disk 202, insulating structure 414, and inner ring 210. The drive disk 202 and inner ring 210 are conductive plates arranged in parallel to the other, sandwiching insulating structure 414 in-between, forming a parallel plate capacitor. The drive disk 202 is capacitively coupled to the inner ring 210, as illustrated by capacitor 442.

Capacitor 444 (i.e., inner capacitor) is formed by backplate 408, insulating structure 414, and inner ring 210. The backplate 408 and inner ring 210 are conductive plates arranged in parallel, sandwiching insulating structure 414 in-between, forming a parallel plate capacitor. In embodiments, the capacitance value of capacitor 444 is greater than 10 picofarads (pF). The capacitance value is substantially the same at each location of the parallel plate capacitor.

Capacitor 448 is formed by housing bottom side 226 b, insulating structure 414, and backplate 408. The housing bottom side 226 b and backplate 408 are conductive plates arranged in parallel, sandwiching insulating structure 414 in-between, forming a parallel plate capacitor.

Capacitor 449 is formed by housing bottom side 226 b, insulating structure 414, and the inner ring 210. The housing bottom side 226 b and inner ring 210 are conductive plates arranged in parallel, sandwiching insulating structure 414 in-between, forming a parallel plate capacitor.

The first node of capacitor 442 is couplable to RF source 102 via the drive disk 202. The first node of capacitor 448 is coupled to the first node of capacitor 444 via the backplate 408. The second node of capacitor 448 and the first node of capacitor 449 are coupled to the common RF ground 262 via the housing bottom side 226 b.

Inductor 250 is formed by radiating structure 222. The first node of inductor 250 is coupled to the second node of capacitor 444, the second node of capacitor 442, and the second node of capacitor 449 via the inner set of conductive offsets 224 a and the inner ring 210. The second node of inductor 250 is coupled to the first node of capacitor 448 and the second node of capacitor 444 via the outer set of conductive offsets 224 b and the backplate 408.

The inductor 250 and capacitor 444 form a resonant circuit 452 (i.e., LC resonant circuit). Concerning FIG. 4A, the inner ring 210, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, the backplate 408, and the insulating structure 414 form the resonant circuit 452. There is no direct current (DC) connection between any part of the resonant circuit 452 and common RF ground in this arrangement.

The various electrical and mechanical parameters of the structural components that form the inductor and capacitors of resonating structure 400 are selected such that the resonating structure 400 operates (i.e., resonates) at a desired operating frequency.

FIG. 4C illustrates a flowchart of an embodiment method 480 as may be performed by resonating structure 400. At step 482, RF source 102 provides a forward RF wave to drive disk 202. In response, at step 484, the RF wave is transmitted from the drive disk 202 to the radiating structure 222 (i.e., inductor 250) by capacitive coupling across capacitor 442 and capacitor 444.

At step 486, radiating structure 222 radiates electromagnetic waves from the resonating structure 400 to the plasma chamber 106. At step 488, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 5A illustrates a side view of an embodiment resonating structure 500.

Resonating structure 500 may operate as resonating structure 104 in the plasma processing system 100 of FIG. 1 . It is noted that resonating structure 500 is not limited to an application in plasma processing, and other applications are similarly contemplated.

Resonating structure 500 shares several features with resonating structure 400. However, in interface 506 of resonating structure 500, the backplate 208 of resonating structure 400 is merged with the housing bottom side 226 b. Thus, in contrast to resonating structure 400, where the backplate 208 is floating, in resonating structure 500, the housing bottom side 226 b (and effectively the backplate) is connected to common RF ground.

FIG. 5B illustrates a schematic 540 of the embodiment resonating structure 500 of FIG. 5A, also referred to as a single grounded capacitor configuration. Schematic 540 includes RF source 102, capacitor 542, capacitor 544, and inductor 250, which may (or may not) be arranged as shown in FIG. 5B.

Capacitor 542 is formed by drive disk 202, insulating structure 514, and inner ring 210. The drive disk 202 and inner ring 210 are conductive plates arranged in parallel to the other, sandwiching insulating structure 514 in-between, forming a parallel plate capacitor. The drive disk 202 is capacitively coupled to the inner ring 210, as illustrated by capacitor 542. The first node of capacitor 542 is couplable to RF source 102 via the drive disk 202.

Capacitor 544 (i.e., inner capacitor) is formed by housing bottom side 226 b, insulating structure 514, and inner ring 210. The housing bottom side 226 b and inner ring 210 are conductive plates arranged in parallel, sandwiching insulating structure 514 in-between, forming a parallel plate capacitor. In embodiments, the capacitance value of capacitor 544 is greater than 10 picofarads (pF). The capacitance value is substantially the same at each location of the parallel plate capacitor.

Inductor 250 is formed by radiating structure 222. The first node of inductor 250 is coupled to the first node of capacitor 544 and the second node of capacitor 542 via the inner set of conductive offsets 224 a and the inner ring 210. The second node of inductor 250 is coupled to the second node of capacitor 544 and common RF ground 262 via the outer set of conductive offsets 224 b and the housing bottom side 226 b.

The inductor 250 and capacitor 544 form a resonant circuit 552 (i.e., LC resonant circuit). Concerning FIG. 5A, the inner ring 210, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, housing bottom side 226 b, and the insulating structure 514 form the resonant circuit 552.

The various electrical and mechanical parameters of the structural components that form the inductor and capacitors of resonating structure 500 are selected such that the resonating structure 500 operates (i.e., resonates) at a desired operating frequency.

FIG. 5C illustrates a flowchart of an embodiment method 580 as may be performed by resonating structure 500. At step 582, RF source 102 provides a forward RF wave to drive disk 202. In response, at step 584, the RF wave is transmitted from the drive disk 202 to the radiating structure 222 (i.e., inductor 250) by capacitive coupling across capacitor 542 and capacitor 544.

At step 586, radiating structure 222 radiates electromagnetic waves from the resonating structure 500 to the plasma chamber 106. At step 588, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 6A illustrates a side view of an embodiment resonating structure 600. Resonating structure 600 may operate as the resonating structure 104 in the plasma processing system 100 in FIG. 1 . It is noted that the resonating structure 600 is not limited to an application in plasma processing, and other applications are contemplated.

Resonating structure 600 shares several features with resonating structure 200. In contrast to resonating structure 200, where the insulating structure 214 is arranged between the backplate 208 and the inner ring 210 in interface 206, in resonating structure 600, the corresponding backplate 208 and inner ring 210 of resonating structure 200 are directly coupled (i.e., electrically and mechanically)— represented by backplate 608 in FIG. 6A. The inner set of conductive offsets 224 a electrically and mechanically couple the radiating structure 222 to the backplate 608.

In addition, resonating structure 600, in addition to the drive disk 202 includes extended drive disk 602 electrically coupled to the drive disk 202 (represented by black wires). In embodiments, the drive disk 202 is electrically coupled to extended drive disk 602 via wire bonds. In some embodiments, the drive disk 202 is electrically coupled to extended drive disk 602 via ribbon bonds. In other embodiments, the drive disk 202 is electrically and mechanically coupled to extended drive disk 602 via rigid, horizontal, conductive pins or arms. Thus, the RF wave generated by RF source 102 is transmitted from drive disk 202 to extended drive disk 602.

FIG. 6B illustrates a schematic 640 of the embodiment resonating structure 600 of FIG. 6A. Schematic 640 includes RF source 102, capacitor 642, capacitor 646, capacitor 648, capacitor 649, and inductor 250, which may (or may not) be arranged as shown in FIG. 6B.

Capacitor 642 is formed by extended drive disk 602, insulating structure 614, and backplate 608. The extended drive disk 602 and backplate 608 are conductive plates arranged in parallel to the other, sandwiching insulating structure 614 in-between, forming a parallel plate capacitor. The extended drive disk 602 is capacitively coupled to the backplate 608, as illustrated by capacitor 642. The first node of capacitor 642 is couplable to RF source 102 via the drive disk 202 and the extended drive disk 602.

Capacitor 646 (i.e., outer capacitor) is formed by backplate 608, insulating structure 614, and the outer ring 212. The backplate 608 and outer ring 212 are conductive plates arranged in parallel, sandwiching insulating structure 614 in-between, forming a parallel plate capacitor. In embodiments, the capacitance value of capacitor 646 is greater than 10 picofarads (pF). The capacitance value is substantially the same at each location of the parallel plate capacitor.

Capacitor 648 is formed by housing bottom side 226 b, insulating structure 6414, and outer ring 212. The housing bottom side 226 b and outer ring 212 are conductive plates arranged in parallel, sandwiching insulating structure 614 in-between, forming a parallel plate capacitor.

Capacitor 649 is formed by housing bottom side 226 b, insulating structure 614, and backplate 608. The housing bottom side 226 b and backplate 608 are conductive plates arranged in parallel, sandwiching insulating structure 614 in-between, forming a parallel plate capacitor. The first node of capacitor 648 and the first node of capacitor 649 are coupled to the common RF ground 262.

Inductor 250 is formed by radiating structure 222. The first node of inductor 250 is coupled to the first node of capacitor 642, the first node of capacitor 646, and the first node of capacitor 649 via the inner set of conductive offsets 224 a and the backplate 608. The second node of inductor 250 is coupled to the second node of capacitor 646 and the second node of capacitor 648 via the outer set of conductive offsets 224 b and the outer ring 212.

The inductor 250 and the capacitor 646 form a resonant circuit 652 (i.e., LC resonant circuit). Concerning FIG. 6A, the outer ring 212, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, the backplate 608, and the insulating structure 614 form the resonant circuit 652. There is no direct current (DC) connection between any part of the resonant circuit 652 and common RF ground in this arrangement.

The various electrical and mechanical parameters of the structural components that form the inductor and capacitors of resonating structure 600 are selected such that the resonating structure 600 operates/resonates at a desired operating frequency.

FIG. 6C illustrates a flowchart of an embodiment method 680 as may be performed by resonating structure 600. At step 682, RF source 102 provides a forward RF wave to drive disk 202 and extended drive disk 602. In response, at step 684, the RF wave is transmitted from the extended drive disk 602 to the radiating structure 222 (i.e., inductor 250) by capacitive coupling across capacitor 642 and capacitor 646.

At step 686, radiating structure 222 radiates electromagnetic waves from the resonating structure 600 to the plasma chamber 106. At step 688, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 7A illustrates a side view of an embodiment resonating structure 700. Resonating structure 700 may operate as the resonating structure 104 in the plasma processing system 100 in FIG. 1 . It is noted that the resonating structure 700 is not limited to an application in plasma processing, and other applications are contemplated.

Resonating structure 700 shares several features with resonating structure 200. Resonating structure 700 does not include the drive disk 202 of the resonating structures discussed in FIGS. 2A, 3A, 4A, 5A, and 6A. Instead, resonating structure 700 includes a loop structure 702. In the resonating structure 700, the radiating structure 222 is coupled to the RF source 102 by an inductive divider, as described further below.

It should be understood that features from different embodiments previously described (and described afterwards) may be combined to form further embodiments with the loop structure 702 instead of the drive disk 202 unless noted otherwise. And variations or modifications described to one of the embodiments may also apply to other embodiments. This statement is not limiting and features from any embodiment can be used in other embodiments.

FIG. 7B illustrates an embodiment loop structure 702, which may be arranged in the resonating structure 700. Loop structure 702 is an open circle, conductive ring structure with a first end 712 and a second end 716. The first end 712 is coupled to the RF source 102 and used to couple RF power to the radiating structure 222. The second end 716 of the loop structure 702 is coupled to a common RF ground of the resonating structure 700 and the RF source 102.

The center point of the loop structure 702 intersects with the center point of the radiating structure 222. The radius of the loop structure 702 is smaller than the inner radius of the radiating structure 222, such that the loop structure 702 is placed on the same plane and arranged within the inner radius of radiating structure 222.

Although the loop structure 702 in FIG. 7A is shown to be located within a boundary of the inner set of conductive offsets 224 a, the radius and arrangement of the loop structure 702 in the resonating structure 700 are non-limiting.

In an embodiment, the loop structure 702 is arranged between the inner set of conductive offsets 224 a and the outer set of conductive offsets 224 b. In another embodiment, the loop structure 702 is arranged external to the outer set of conductive offsets 224 b. In such an embodiment, the loop structure 702 has a radius greater than the outer radius of the radiating structure 222. In yet another embodiment, the loop structure 702 has a diameter that is less than the diameter of the inner set of conductive offsets 224 a. In such an embodiment, the loop structure 702 can be on a different plane (e.g., above or below the plane of the radiating structure 222). In all embodiments, non-conductive offsets may connect to the loop structure 702 to improve structural rigidity.

FIG. 7C illustrates a schematic 720 of the embodiment resonating structure 700 of FIG. 7A. Schematic 720 includes RF source 102, inductor 722, inductor 724, inductor 726, capacitor 728, capacitor 730, and capacitor 732, which may (or may not) be arranged as shown in FIG. 7C.

Inductor 722 is formed by the loop structure 702. The first node of the loop structure 702 is coupled to the RF source 102 via the first end 712. The second node of the loop structure 702 is coupled to a common RF ground of the resonating structure 700 and the RF source 102 via the second end 716.

Inductor 724 is formed by the radiating structure 222. Inductor 722 is inductively coupled to inductor 724 (i.e., the radiating structure 222) in response to the RF source 102 transmitting a forward RF wave to the first end 712 of the loop structure 702.

Inductor 726 is formed by the radiating structure 222. Although inductor 522 and inductor 524 are shown as separate components, a single inductor can also represent inductor 522 and inductor 524 because they represent the radiating structure 222.

Capacitor 728 is formed by the backplate 208, the insulating structure 714, and the inner ring 210. The backplate 208 and inner ring 210 are conductive plates arranged in parallel, sandwiching insulating structure 714 in-between, forming a parallel plate capacitor.

Capacitor 730 is formed by the backplate 208, the insulating structure 714, and the outer ring 212. The backplate 208 and outer ring 212 are conductive plates arranged in parallel, sandwiching insulating structure 714 in-between, forming a parallel plate capacitor.

Capacitor 732 is formed by housing bottom side 226 b, insulating structure 714, and the backplate 208. The backplate 208 and housing bottom side 226 b are conductive plates arranged in parallel, sandwiching insulating structure 714 in-between, forming a parallel plate capacitor.

The first node of capacitor 732 is coupled to the common RF ground 262 via the housing bottom side 226 b. The second node of capacitor 732 is coupled to the first node of capacitor 730 and the first node of capacitor 728 via the backplate 208.

A node of inductor 726 is coupled to the second node of capacitor 730 via the outer set of conductive offsets 224 b and the outer ring 212.

A node of inductor 724 is coupled to the second node of capacitor 728 via the inner set of conductive offsets 224 a and the inner ring 210.

The inductor 724, inductor 726, capacitor 728, and capacitor 730 form the resonant circuit 752 (i.e., LC resonant circuit). Regarding FIG. 7A, the inner ring 210, the outer ring 212, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, the backplate 208, and the insulating structure 714 form the resonant circuit 752. There is no direct current (DC) connection between any part of the resonant circuit 752 and common RF ground in this arrangement.

The various electrical and mechanical parameters of the structural components that form the inductors and capacitors of resonating structure 700 are selected such that the resonating structure 700 operates/resonates at a desired operating frequency.

FIG. 7D illustrates a flowchart of an embodiment method 760 as may be performed by resonating structure 700. At step 762, RF source 102 provides a forward RF wave to loop structure 702 via the first end 712. In response, at step 764, the RF wave is transmitted from the loop structure 702 to the radiating structure 222 (i.e., inductor 726) by inductive coupling across inductor 722 and inductor 724.

At step 766, radiating structure 222 radiates electromagnetic waves from the resonating structure 700 to the plasma chamber 106. At step 768, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 8A illustrates a side view of an embodiment resonating structure 800. Resonating structure 800 may operate as resonating structure 104 in the plasma processing system 100 of FIG. 1 . It is noted that resonating structure 800 is not limited to an application in plasma processing, and other applications are similarly contemplated.

Resonating structure 800 shares several features with resonating structure 300. In resonating structure 800, the drive disk 202 in resonating structure 800 is placed between the inner ring 210 and the housing bottom side 226 b. In this embodiment, similar to the resonating structure 300, the backplate 208 is infused within the housing bottom side 226 b.

FIG. 8B illustrates a schematic 840 of the embodiment resonating structure 800 of FIG. 8A, also referred to as a double grounded capacitor configuration. Schematic 840 includes RF source 102, capacitor 844, capacitor 846, capacitor 848, and inductor 250, which may (or may not) be arranged as shown in FIG. 8B.

Capacitor 842 (i.e., inner capacitor) is formed by drive disk 202, insulating structure 814, and the inner ring 210. The drive disk 202 and inner ring 210 are conductive plates arranged in parallel to the other, sandwiching insulating structure 814 in-between, forming a parallel plate capacitor.

In embodiments, the drive disk 202 is capacitively couplable to the inner ring 210 as illustrated by capacitor 842.

Capacitor 844 (i.e., outer capacitor) is formed by housing bottom side 226 b, insulating structure 814, and the outer ring 211. The housing bottom side 226 b and outer ring 212 are conductive plates arranged in parallel, sandwiching insulating structure 814 in-between, forming a parallel plate capacitor. The first node of the capacitor 844 is coupled to common RF ground 262 via the housing bottom side 226 b.

Capacitor 846 is formed by housing bottom side 226 b, insulating structure 814, and drive disk 202. The housing bottom side 226 b and the drive disk 202 are conductive plates arranged in parallel, sandwiching insulating structure 814 in-between, forming a parallel plate capacitor. The first node of the capacitor 846 is coupled to common RF ground 262 via the housing bottom side 226 b.

The first node of capacitor 842 and the second node of capacitor 846 is couplable to RF source 102 via the drive disk 202.

Inductor 250 is formed by radiating structure 222. The first node of inductor 250 is coupled to the second node of capacitor 842 via the inner set of conductive offsets 224 a and the inner ring 210. The second node of inductor 250 is coupled to the second node of capacitor 844 via the outer set of conductive offsets 224 b and the outer ring 212.

In embodiments, the RF source 102 is electromagnetically coupled to each of the inner ring 210 and housing bottom side 226 b via the drive disk 202.

The inductor 25 o, capacitor 842, capacitor 844, and capacitor 846 form a resonant circuit 852 (i.e., LC resonant circuit). Concerning FIG. 8A, the inner ring 210, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, the outer ring 212, the housing bottom side 226 b, and the insulating structure 814 form the resonant circuit 852.

In embodiments where the resonating structure 800 is used in plasma processing, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

The various electrical and mechanical parameters of the structural components that form the inductors and capacitors of resonating structure 800 are selected such that the resonating structure 800 operates (i.e., resonates) at a desired operating frequency. In embodiments, the RF source 102 is configured to feed an RF power to the resonant circuit 852.

FIG. 8C illustrates a flowchart of an embodiment method 860 as may be performed by resonating structure 800. At step 862, RF source 102 provides a forward RF wave to drive disk 202. In response, at step 864, the RF wave is transmitted from the drive disk 202 to the radiating structure 222 (i.e., inductor 250) by capacitive coupling across capacitor 842, capacitor 844, and capacitor 846.

At step 866, radiating structure 222 radiates electromagnetic waves from the resonating structure 800 to the plasma chamber 106. At step 868, the electromagnetic waves generate plasma 112. The plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 9A illustrates a side view of an embodiment resonating structure 900. In resonating structure 900, in place of the outer set of conductive offsets 224 b of resonating structure 700, resonating structure 900 includes an outer set of non-conductive offsets 924. The outer set of non-conductive offsets 924 provide structural rigidity to the outer portion of the radiating structure 222 by mechanically connecting the backplate 208 to radiating structure 222. However, it should be appreciated that in embodiments, the outer set of non-conductive offsets 924 can be omitted from the structure and the portion of the radiating structure 222 shown to be connected to the outer set of non-conductive offsets 924 can be floating.

FIG. 9B illustrates a schematic 940 of the embodiment resonating structure 900 of FIG. 9A. Schematic 940 includes, in addition to the components disclosed in schematic 720, a distributed constant circuit 954, which may (or may not) be arranged as shown in FIG. 9B. The distributed constant circuit 954 includes a plurality of inductors 926 and capacitors 930 formed by the spiral arms of the radiating structure 222 and the backplate 208. Even though the spiral arms of the radiating structure 222 and the backplate 208 have no direct electrical connection, the spiral arms of the radiating structure 222 and the backplate 208 have “weak” electrical (i.e., capacitive coupling)—non-negligible electrical coupling, which form the distributed constant circuit 954. The capacitors 930 provide a small capacitance value that brings about a gradual change in voltage and current along the spiral arms of the radiating structure 222—no lumped capacitance.

The inductor 724, inductor 726, capacitor 728, inductors 926, and capacitors 930 form the resonant circuit 952 (i.e., LC resonant circuit). Regarding FIG. 9A, the inner ring 210, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, the backplate 208, and the insulating structure 714 form the resonant circuit 952. There is no direct current (DC) connection between any part of the resonant circuit 952 and common RF ground in this arrangement.

The various electrical and mechanical parameters of the structural components that form the inductors and capacitors of resonating structure 900 are selected such that the resonating structure 900 operates/resonates at a desired operating frequency.

FIG. 9C illustrates a flowchart of an embodiment method 960 as may be performed by resonating structure 900. At step 962, RF source 102 provides a forward RF wave to loop structure 702 via the first end 712. In response, at step 964, the RF wave is transmitted from the loop structure 702 to the radiating structure 222 (i.e., inductor 726, inductors 926) by inductive coupling across inductor 722 and inductor 724.

At step 966, radiating structure 222 radiates electromagnetic waves from the resonating structure 900 to the plasma chamber 106. At step 968, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 10A illustrates a side view of an embodiment resonating structure 100. In resonating structure 100, in place of the inner set of conductive offsets 224 a of resonating structure 700, resonating structure 100 includes an inner set of non-conductive offsets 1024. The inner set of non-conductive offsets 1024 provide structural rigidity to the inner portion of the radiating structure 222 by mechanically connecting the backplate 208 to radiating structure 222. However, it should be appreciated that in embodiments, the inner set of non-conductive offsets 1024 can be omitted from the structure, and the portion of the radiating structure 222 shown to be connected to the inner set of non-conductive offsets 1024 can be floating.

FIG. 10B illustrates a schematic 1040 of the embodiment resonating structure 100 of FIG. 10A. Similar to schematic 940, schematic 1040 includes a distributed constant circuit 1054. The distributed constant circuit 1054 includes a plurality of inductors 1026 and capacitors 1030 formed by the spiral arms of the radiating structure 222 and the backplate 208. Even though the spiral arms of the radiating structure 222 and the backplate 208 have no direct electrical connection, the spiral arms of the radiating structure 222 and the backplate 208 have “weak” electrical (i.e., capacitive coupling)—non-negligible electrical coupling, which form the distributed constant circuit 1054. The capacitors 1030 provide a small capacitance value that brings about a gradual change in voltage and current along the spiral arms of the radiating structure 222—no lumped capacitance.

The inductor 724, inductor 726, capacitor 728, inductors 1026, and capacitors 1030 form the resonant circuit 1052 (i.e., LC resonant circuit). Regarding FIG. 10A, the inner ring 210, the inner set of conductive offsets 224 a, the radiating structure 222, the outer set of conductive offsets 224 b, the backplate 208, and the insulating structure 714 form the resonant circuit 1052. There is no direct current (DC) connection between any part of the resonant circuit 1052 and common RF ground in this arrangement.

The various electrical and mechanical parameters of the structural components that form the inductors and capacitors of resonating structure 100 are selected such that the resonating structure 100 operates/resonates at a desired operating frequency.

FIG. 10C illustrates a flowchart of an embodiment method 1060 as may be performed by resonating structure woo. At step 1062, RF source 102 provides a forward RF wave to loop structure 702 via the first end 712. In response, at step 1064, the RF wave is transmitted from the loop structure 702 to the radiating structure 222 (i.e., inductor 726, inductors 1026) by inductive coupling across the inductor 722 and inductor 724.

At step 1066, radiating structure 222 radiates electromagnetic waves from the resonating structure 100 to the plasma chamber 106. At step 1068, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 11A illustrates a side view of an embodiment resonating structure 1100. Resonating structure 1100 may operate as resonating structure 104 in the plasma processing system 100 of FIG. 1 . It is noted that resonating structure 1100 is not limited to an application in plasma processing, and other applications are similarly contemplated.

In resonating structure 1100, in contrast to the previous embodiments where the conductive structures forming the various capacitive plates were arranged parallel to the housing bottom side 226 b, the conductive structures forming the different capacitive plates are arranged perpendicular to the housing bottom side 226 b.

Resonating structure 1100 includes a cylindrical structure 1102 and a cylindrical ring structure 1112.

Cylindrical structure 1102 is a conductive, hollow, cylindrical structure having an open side near the housing top side 226 c and a closed side near the housing bottom side 226 b. Further, cylindrical structure 1102 includes conductive walls 1104. The closed side of the cylindrical structure 1102 is electrically coupled to the RF source 102, which feeds an RF wave to the conductive walls 1104. The inner, hollow portion of cylindrical structure 1102 is encased with the insulating structure 1114. In embodiments, the inner, hollow portion of cylindrical structure 1102 is filled with air.

The cylindrical ring structure 1112 is a conductive, hollow, cylindrical ring structure having an inner conductive wall 1108 and an outer conductive wall 1106. The top portion of the cylindrical ring structure 1112 includes the radiating structure 222. Thus, the inner conductive wall 1008 and outer conductive wall 1106 are arranged in parallel but perpendicular to the radiating structure 222. The bottom portion of cylindrical ring structure 1112 is open, and the inner, hollow portion of cylindrical ring structure 1112 is encased with insulating structure 1114.

The inner ring of the cylindrical ring structure 1112 encircles the cylindrical structure 1102, such that the inner conductive wall 1108 of the cylindrical ring structure 1112 are arranged in parallel to the conductive wall 1104 of the cylindrical structure 1102. In embodiments, the insulating structure 1114 is arranged in between the inner conductive wall 1108 of the cylindrical ring structure 1112 and the conductive wall 1104 of the cylindrical structure 1102.

The outer conductive wall 1106 is arranged in parallel to the housing sidewall 226 a. In embodiments, the insulating structure 1114 is arranged in between the outer conductive wall 1106 of the cylindrical ring structure 1112 and the housing sidewall 226 a. The housing sidewall 226 a and the housing bottom side 226 b are electrically coupled to a common RF ground of the resonating structure 1100 and RF source 102.

Finally, housing 226 a-c further includes housing inner wall 226 d, which creates a hollow cylindrical shape in combination with the housing bottom side 226 b and is arranged in parallel with the inner conductive wall 1108. In embodiments, the insulating structure 1114 is arranged in between the inner conductive wall 1108 of the cylindrical ring structure 1112 and the housing inner wall 226 d.

It should be appreciated the arrangement of the structure coupling the RF wave from the RF source 102 to the radiating structure 222 may be in various shapes and, thus, non-limiting. Further, although the RF source 102 is electrically coupled to the center of the resonating structure 1100 via the conductive wall 1104 of the cylindrical structure 1102, it should be appreciated that, in embodiments, the RF source 102 is electrically coupled to the cylindrical ring structure 1112, the cylindrical structure 1102, or the combination of the two.

FIG. 11B illustrates a schematic 1140 of the embodiment resonating structure 1100 of FIG. 11A. Schematic 1140 includes RF source 102, capacitor 1142, capacitor 1144, capacitor 1146, capacitor 1148, and inductor 250, which may (or may not) be arranged as shown in FIG. 11B.

Capacitor 1142 is formed by conductive wall 1104 of the cylindrical structure 1102, insulating structure 1114, and housing inner wall 226 d. The conductive wall 1104 of the cylindrical structure 1102 and housing inner wall 226 d are conductive, cylinders arranged in concentric to the other, sandwiching insulating structure 1114 in-between, forming a cylindrical capacitor. The conductive wall 1104 of the cylindrical structure 1102 is electrically coupled to the RF source 102. The housing inner wall 226 d is electrically coupled to the common RF ground.

Capacitor 1144 is formed by conductive walls 1104 of the cylindrical structure 1102, insulating structure 1114, and inner conductive wall 1108 of the cylindrical ring structure 1112. The conductive wall 1104 of the cylindrical structure 1102 and inner conductive wall 1108 of the cylindrical ring structure 1112 are conductive, cylinders arranged concentric to the other, sandwiching insulating structure 1114 in-between, forming a cylindrical capacitor.

Capacitor 1146 is formed by housing inner wall 226 d, insulating structure 1114, and inner conductive wall 1108 of the cylindrical ring structure 1112. The housing inner wall 226 d and inner conductive wall 1108 of the cylindrical ring structure 1112 are conductive, cylinders arranged concentric to the other, sandwiching insulating structure 1114 in-between, forming a cylindrical capacitor.

Capacitor 1148 is formed by housing sidewall 226 a, insulating structure 1114, and outer conductive wall 1106 of the cylindrical ring structure 1112. The housing sidewall 226 a and outer conductive wall 1106 of the cylindrical ring structure 1112 are conductive, cylinders arranged concentric to the other, sandwiching insulating structure 1114 in-between, forming a cylindrical capacitor.

The first node of capacitor 1142 and the first node of capacitor 1144 are couplable to RF source 102 via the conductive wall 1104 of the cylindrical structure 1102. The first node of capacitor 1146, the first node of capacitor 1148, and the second node of capacitor 1142 are coupled to the common RF ground 262 via housing inner wall 226 d.

Inductor 250 is formed by radiating structure 222. The first node of inductor 250 is coupled to the second node of capacitor 1144 and the second node of capacitor 1146 via the inner conductive wall 1108 of the cylindrical ring structure 1112. The second node of inductor 250 is coupled to the second node of capacitor 1148 via the outer conductive wall 1106 of the cylindrical ring structure 1112.

The inductor 250, capacitor 1146, and capacitor 1148 form a resonant circuit 1152 (i.e., LC resonant circuit). Regarding FIG. 11A, the housing inner wall 226 d, insulating structure 1114, inner conductive wall 1108 of the cylindrical ring structure 1112, and outer conductive wall 1106 of the cylindrical ring structure 1112 and housing sidewall 226 a form the resonant circuit 1152.

The various electrical and mechanical parameters of the structural components that form the inductors and capacitors of resonating structure 1100 are selected such that the resonating structure 1100 operates (i.e., resonates) at a desired operating frequency.

FIG. 11C illustrates a flowchart of an embodiment method 1160 as may be performed by resonating structure 1100. At step 1162, RF source 102 provides a forward RF wave to the conductive wall 1104 of the cylindrical structure 1102. In response, at step 1164, the RF wave is transmitted from the conductive wall 1104 of the cylindrical structure 1102 to the radiating structure 222 (i.e., inductor 250) by capacitive coupling across capacitor 1142, capacitor 1144, capacitor 1146, and capacitor 1148.

At step 1166, radiating structure 222 radiates electromagnetic waves from the resonating structure 1100 to the plasma chamber 106. At step 1168, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 12 illustrates a top view of an embodiment radiating structure 1200. In embodiments, radiating structure 1200 is also referred to as an antenna plate. Radiating structure 1200 has an inner radius 1202, an outer radius 1204, and a center point 1206.

In embodiments, the inner radius 1202 of the radiating structure 1200 is substantially the same but slightly larger than an outer radius of the loop structure 702. In such an embodiment, the center point 1206 of the radiating structure 1200 is the same as the center point of the loop structure 702.

In embodiments, the inner radius 1202 of the radiating structure 1200 is substantially the same but slightly smaller than an outer radius of the inner ring 210. In such an embodiment, the center point 1206 of the radiating structure 1200 is the same as the center point of the inner ring 210. Thus, the inner set of conductive offsets 224 a can be placed perpendicular between the inner ring 210 and the radiating structure 1200.

In embodiments, the outer radius 1204 of the radiating structure 1200 is substantially the same as an outer radius of the outer ring 212. In such an embodiment, the center point 1206 of the radiating structure 1200 is the same as the center point of the outer ring 212. Thus, the outer set of conductive offsets 224 b can be placed perpendicular between the outer ring 212 and the radiating structure 1200.

In embodiments, radiating structure 1200 is a conductive, planar, closed ring structure with a plurality of spiral arms 1208. The spiral arms 1208 have n-fold symmetry about an axis which passes through the center point 1206. In FIG. 12 , the number of spiral arms 1208 is shown to be eight; however, the number of spiral arms 1208 is non-limiting and can be any number greater than one.

In embodiments, radiating structure 1200 is a monolithic structure. In such an embodiment, the radiating structure 1200 includes a closed inner ring and a closed outer ring, which provide mechanical connections to hold the spiral arms 1208 into a single unit.

In embodiments, the individual spiral arms 1208 are formed using, for example, copper tubing that individually connect the inner set of conductive offsets 224 a to the outer set of conductive offsets 224 b. In embodiments, the individual spiral arms 1208 are formed by individually machined pieces made from, for example, aluminum that individually connect the inner set of conductive offsets 224 a to the outer set of conductive offsets 224 b. In such embodiments, there is no per se inner ring or outer ring such as that in the monolithic structure.

In embodiments, the radiating structure 1200 is a conductive plate with a plurality of axisymmetric spiral cutouts that form the plurality of spiral arms 1208. In embodiments where the radiating structure 1200 is formed from a conductive plate, the assembly and mechanical inconsistencies of the resonating structure are minimized due to the generally tight tolerances in the fabrication and manufacturing of the radiating structure 1200. Advantageously, such a structure provides for more robust and repeatable electromagnetic waves. Furthermore, the radiating structure 1200 design provides for scaling to accommodate multiple radial zones with respect to the generated electromagnetic fields.

In embodiments, the various capacitive structures allow shorter antenna segments and axisymmetry.

In embodiments, the radiating structure 1200 reduces unwanted dielectric etching and sputtering due to the high sheath electric fields generated by the resonating structure when used in plasma processing. The resonating structure reduces the dielectric etching and sputtering by shifting the high electric fields to the inner and outer capacitors of the resonating structure and placing the high magnetic fields nearest to the plasma.

In embodiments, the endpoints of each spiral arm 1208 are disposed at different angles measured from the center point 1206 of the radiating structure 1200.

In embodiments, the arrangement of the spiral arms 1208 includes arranging the spiral arms in an arc between ends of any combination of conductive offsets 224 a-b or non-conductive offsets of any resonating structures previously disclosed.

In embodiments, the arrangement of the spiral arms 1208 includes arranging the spiral arms 1208 in an arc between ends of any pair of one of the inner set of conductive offsets 224 a and one of the outer set of conductive offsets 224 b. In such an embodiment, the distal ends of each corresponding pair is connected to any interface of any resonating structure previously disclosed.

In embodiments, each spiral arm 1208 is additionally supported by one or more non-conductive offsets along the arc of the spiral arm 1208.

In embodiments, respective ends of each spiral arm 1208, as measured from a center of each spiral arm 1208, have different radii. In embodiments, respective ends of each spiral arm 1208, as measured from a center of each spiral arm 1208, have different radial angles. In embodiments, the radial angles of each spiral arm are symmetric.

In embodiments, each spiral arm 1208 has a straight line distance between its ends. In such an embodiment, a straight line distance of a majority of the spiral arms 1208 is of the same or a similar length.

In embodiments, the arrangement of spiral arms 1208 includes arranging the spiral arms 1208 such that geometry of the spiral arms 1208 is unchanged during a rotation of all the spiral arms 1208 about an axis of symmetry by an angle equal to 2.0π divided by an integer greater than 2. In an exemplary embodiment, the integer is equal to eight.

In embodiments, the radiating structure 1200 is semi-axisymmetric. In embodiments, the spiral arms 1208 have an eight-fold symmetry.

As shown, the spiral arms 1208 have a design corresponding to Archimedean spirals forming a spiral antenna. However, the design of the radiating structure 222 is non-limiting. For example, in embodiments, the spiral arms 1208 can be in the shape of logarithmic spirals forming a spiral antenna. Further, the radiating structure 1200 is not limited to a spiral antenna. For example, the radiating structure 1200 can be a coil antenna or a disk antenna in embodiments. As another example, the radiating structure 1200 can be a single coil arc plate, a double coil arc plate, or a uni-body arc plate.

Radiating structure 1200 is shown as a solid conductive plate having cutouts to form the spiral arms 1208. However, it should be appreciated that in embodiments, the radiating structure 1200 can include a plurality of wires arranged in a spiral configuration. Each wire is connected to an inner ring on one end and an outer ring on the other in such an embodiment. For example, with reference to the resonating structure 200, each of the inner set of conductive offsets 224 a is connected to the inner ring, and each of the outer set of conductive offsets 224 b is connected to the outer ring.

In embodiments, the radiating structures disclosed herein provide a uniform electromagnetic field within the plasma chamber 106. The uniform electromagnetic field provides for a uniform distribution of the density of the plasma 112 and, thus, uniform substrate treatment within.

In embodiments, the spiral arms 1208 geometrically wind in a radial and azimuthal manner. In embodiments, the spiral arms 1208 are positioned in a nested manner.

In embodiments, each of the spiral arms 1208 has the same shape, length, and volume as the rest of the spiral arms 1208.

FIG. 13A illustrates a side view of an embodiment resonating structure 1300.

Resonating structure 1300 may operate as resonating structure 104 in the plasma processing system 100 of FIG. 1 . It is noted that resonating structure 1300 is not limited to an application in plasma processing, and other applications are similarly contemplated.

Resonating structure 1300 includes an inner radiating structure 1322 a and an outer radiating structure 1322 b. Inner radiating structure 1322 a and outer radiating structure 1322 b are concentric, conductive ring structures with the same center point. The outer radius of the inner radiating structure 1322 a is less than an inner radius of the outer radiating structure 1322 b.

Moreover, interface 1306 of resonating structure 1300 includes a first inner ring 1302, a second inner ring 1308, a first outer ring 1310, and a second outer ring 1312 in place of the inner ring 210 and outer ring 212 of the resonating structure 700. The first inner ring 1302, the second inner ring 1308, the first outer ring 1310, and the second outer ring 1312 are conductive, ring structures substantially parallel to each other and backplate 208.

The first inner ring 1302 is disposed between the loop structure 702 and RF source 102. The second inner ring 1308 is disposed between the first inner ring 1302 and RF source 102. The first outer ring 1310 is disposed between the loop structure 702 and the RF source 102. The second outer ring 1312 is disposed between the first outer ring 1310 and the RF source 102.

The first inner ring 1302 and the first outer ring 1310 are shown to be substantially on the same plane and have the same center point. However, in embodiments, the first inner ring 1302 and the first outer ring 1310 are on a different plane. The first inner ring 1302 has an outer radius smaller than the inner radius of the first outer ring 1310.

The second inner ring 1308 and the second outer ring 1312 are shown to be substantially on the same plane and have the same center point. However, in embodiments, the second inner ring 1308 and the second outer ring 1312 are on a different plane. The second inner ring 1308 has an outer radius smaller than the inner radius of the second outer ring 1312.

Resonating structure 1300 includes conductive offsets 224 c-d in addition to the conductive offsets 224 a-b of resonating structure 700. As shown, conductive offsets 224 a-d are arranged perpendicular to interface 1306, the inner radiating structure 1322 a, and the outer radiating structure 1322 b. However, any of the conductive offsets 224 a-d can also be arranged such that they vertically connect interface 1306 to inner radiating structure 1322 a and outer radiating structure 1322 b without being perpendicular to these surfaces.

Conductive offsets 224 a-d include a first inner set of conductive offsets 224 a, a second inner set of conductive offsets 224 c, a first outer set of conductive offsets 224 d, and a second outer set of conductive offsets 224 b.

As shown, the first inner set of conductive offsets 224 a electrically couple the first inner ring 1302 to an inner portion of the inner radiating structure 1322 a. The second inner set of conductive offsets 224 c electrically couple the second inner ring 1308 to an outer portion of the inner radiating structure 1322 a. The first outer set of conductive offsets 224 d electrically couple the first outer ring 1310 to an inner portion of the outer radiating structure 1322 b. And, the second outer set of conductive offsets 224 b electrically couple the second outer ring 1312 to an outer portion of the outer radiating structure 1322 b.

In an embodiment, an end of each first inner set of conductive offsets 224 a is arranged at an equal distance from each other along the surface of the first inner ring 1302. In an embodiment, an end of each second inner set of conductive offsets 224 c is arranged at an equal distance from each other along the surface of the second inner ring 1308. In an embodiment, an end of each first outer set of conductive offsets 224 d is arranged at an equal distance from each other along the surface of the first outer ring 1310. And, in an embodiment, an end of each second outer set of conductive offsets 224 b is arranged at an equal distance from each other along the surface of the second outer ring 1312.

In embodiments, non-conductive offsets (not shown) may provide additional structural rigidity to resonating structure 1300 by mechanically connecting the inner radiating structure 1322 a and the outer radiating structure 1322 b to the interface 1306.

The insulating structure 1314 consists of an electrically insulating material such as a dielectric or the like. The insulating structure 1314 is arranged between the first inner ring 1302 and the second inner ring 1308, between the first inner ring 1302 and the first outer ring 1310, between the first outer ring 1310 and the second outer ring 1312, between the second inner ring 1308 and the second outer ring 1312, and between each of the second inner ring 1308 and second outer ring 1312 and backplate 208.

FIG. 13B illustrates a schematic 1340 of the embodiment resonating structure 1300 of FIG. 13A. Schematic 1340 includes RF source 102, inductor 722, inductor 1342, inductor 1344, inductor 1346, inductor 1348, capacitor 1350, capacitor 1352, capacitor 1351, and capacitor 1353, which may (or may not) be arranged as shown in FIG. 13B.

Inductor 722 is formed by the loop structure 702. A first node of the loop structure 702 is coupled to the RF source 102, and a second node of the loop structure 702 is coupled to a common RF ground of the resonating structure 1300.

Inductor 1342 is formed by the inner radial structure of inner radiating structure 1322 a—the portion of the inner radiating structure 1322 a that is mechanically connected to the first inner set of conductive offsets 224 a. Inductor 1342 (i.e., the inner radiating structure 1322 a) is inductively coupled to inductor 722 in response to the RF source 102 providing an RF wave to the first end 712 of the loop structure 702.

Inductor 1346 is formed by the inner radial structure of outer radiating structure 1322 b—the portion of the outer radiating structure 1322 b that is mechanically connected to the first outer set of conductive offsets 224 d. Inductor 1346 (i.e., the outer radiating structure 1322 b) is inductively coupled to inductor 722 in response to the RF source 102 providing RF power to the first end 712 of the loop structure 702.

Inductor 1344 is formed by the inner radiating structure 1322 a. The inner radiating structure 1322 a as a whole forms inductor 1342 and inductor 1344, which a single inductor can represent.

Inductor 1348 is formed by the outer radiating structure 1322 b. The outer radiating structure 1322 b as a whole forms inductor 1346 and inductor 1348, which a single inductor can represent.

Capacitor 1350 is formed by the first inner ring 1302, insulating structure 1314, and the second inner ring 1308. The first inner ring 1302 and the second inner ring 1308 are conductive, concentric plates arranged in parallel, sandwiching insulating structure 1314 in-between, forming a parallel plate capacitor.

Capacitor 1352 is formed by the first outer ring 1310, insulating structure 1314, and the second outer ring 1312. The first outer ring 1310 and the second outer ring 1312 are conductive, concentric plates arranged in parallel, sandwiching insulating structure 1314 in-between, forming a parallel plate capacitor.

Capacitor 1351 is formed by the second inner ring 1308, insulating structure 1314, and the backplate 208. The second inner ring 1308 and the backplate 208 are conductive, concentric plates arranged in parallel, sandwiching insulating structure 1314 in-between, forming a parallel plate capacitor. The backplate 208 is connected to a common RF ground of the resonating structure 1300. However, in embodiments, the backplate 208 may be left floating.

Capacitor 1353 is formed by the second outer ring 1312, insulating structure 1314, and the backplate 208. As shown, the second outer ring 1312 and the backplate 208 are conductive, concentric plates arranged in parallel, sandwiching insulating structure 1314 in-between, forming a parallel plate capacitor. As shown, the backplate 208 is connected to the common RF ground of the resonating structure 1300. However, in embodiments, the backplate 208 may be left floating.

A node of inductor 1342 is coupled to the first node of capacitor 1350 via the second inner set of conductive offsets 224 c and the second inner ring 1308. A node of inductor 1346 is coupled to the first node of capacitor 1352 via the second outer set of conductive offsets 224 b and the second outer ring 1312. A node of inductor 1344 is coupled to the second node of capacitor 1350 via the first inner set of conductive offsets 224 a and the first inner ring 1302. A node of inductor 1348 is coupled to the second node of capacitor 1352 via the first outer set of conductive offsets 224 d and the first outer ring 1310.

The inductor 1342, inductor 1344, and capacitor 1350 form an inner resonant circuit 1354 (i.e., LC resonant circuit). Regarding FIG. 13A, the first inner ring 1302, the insulating structure 1314, the second inner ring 1308, the first inner set of conductive offsets 224 a, the second inner set of conductive offsets 224 c, the inner radiating structure 1322 a, and the backplate 208 form the inner resonant circuit 1354.

The inductor 1346, inductor 1348, and capacitor 1352 form an outer resonant circuit 1356 (i.e., LC resonant circuit). Regarding FIG. 13A, the first outer ring 1310, the insulating structure 1314, the second outer ring 1312, the first outer set of conductive offsets 224 d, the second outer set of conductive offsets 224 b, the outer radiating structure 1322 b, and the backplate 208 form the outer resonant circuit 1356.

The various electrical and mechanical parameters of the structural components that form the inductors and capacitors of resonating structure 1300 are selected such that the resonating structure 1300 operates/resonates at a desired operating frequency.

In embodiments, the inner resonant circuit 1354 operates at a first resonant frequency, and the outer resonant circuit 1356 operates at a second resonant frequency. In embodiments, the second resonant frequency is different from the first resonant frequency. In other embodiments, the first resonant frequency is the same as the second resonant frequency.

In embodiments where the second resonant frequency is different from the first resonant frequency, a first inner zone of plasma and a second outer zone of plasma are, respectively, generated by the inner resonant circuit 1354 and the outer resonant circuit 1356 within the plasma chamber 106. The inner resonant circuit 1354 and the outer resonant circuit 1356 can function as an inductive pickup for power, inductive coupling to the plasma, or both.

In embodiments, the RF source 102 is configured to feed an RF power to the inner resonant circuit 1354 and the outer resonant circuit 1356. In such embodiments, the RF source 102 provides an RF wave with a superposition of two co-propagating waves with different frequencies corresponding to the first resonant frequency and the second resonant frequency.

FIG. 13C illustrates a flowchart of an embodiment method 1360 as may be performed by the inner resonant circuit 1354 of resonating structure 1300. At step 1362, RF source 102 provides a forward RF wave to loop structure 702 via the first end 712. In response, at step 1364, the RF wave is transmitted from the loop structure 702 to the inner radiating structure 1322 a by inductive coupling across inductor 722 and inductor 1342.

At step 1366, inner radiating structure 1322 a radiates electromagnetic waves from the inner resonant circuit 1354 of resonating structure 1300 to the plasma chamber 106. At step 1368, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 13D illustrates a flowchart of an embodiment method 1380 as may be performed by the outer resonant circuit 1356 of resonating structure 1300. At step 1382, RF source 102 provides a forward RF wave to loop structure 702 via the first end 712. In response, at step 1384, the RF wave is transmitted from the loop structure 702 to the outer radiating structure 1322 b by inductive coupling across inductor 722 and inductor 1346.

At step 1386, outer radiating structure 1322 b radiates electromagnetic waves from the outer resonant circuit 1356 of resonating structure 1300 to the plasma chamber 106. At step 1388, the electromagnetic waves generate plasma 112. In such an embodiment, the plasma generated by the RF discharge is classified as a purely inductive coupled plasma.

FIG. 14 illustrates a top view of an embodiment radiating structure 1400 having an inner radiating structure 1402 and an outer radiating structure 1404. In embodiments, the inner radiating structure 1322 a and the outer radiating structure 1322 b of resonating structure 1300 are represented, respectively, by the inner radiating structure 1402 and the outer radiating structure 1404.

The inner radiating structure 1402 and outer radiating structure 1404 are concentric, conductive, ring structures with spiral cutouts. The inner radiating structure 1402 is located within the inner ring cutout of the outer radiating structure 1404 and on the same plane as the outer radiating structure 1404 with the same centerpoint. Each of the inner radiating structure 1402 and outer radiating structure 1404 form a spiral antenna.

Although the description has been described in detail, it should be understood that various changes, substitutions, and alterations may be made without departing from the spirit and scope of this disclosure as defined by the appended claims. The same elements are designated with the same reference numbers in the various figures. Moreover, the scope of the disclosure is not intended to be limited to the particular embodiments described herein, as one of ordinary skill in the art will readily appreciate from this disclosure that processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, may perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

The specification and drawings are, accordingly, to be regarded simply as an illustration of the disclosure as defined by the appended claims, and are contemplated to cover any and all modifications, variations, combinations, or equivalents that fall within the scope of the present disclosure. It should be appreciated that the physical arrangement and disposition of the components in the various embodiments of, for example, the plasma processing system or the resonating structures are non-limiting. For example, although the resonating structure is arranged between the RF source and the plasma processing system in the various illustrations, this arrangement is non-limiting, and these components may be arranged adjacent, above, or below the other components while within the scope of the present disclosure. 

What is claimed is:
 1. An apparatus for a plasma processing system, the apparatus comprising: an interface comprising: a first conductive plate couplable to an RF source, a second conductive plate disposed between the RF source and the first conductive plate, and conductive concentric ring structures disposed between the second conductive plate and a substrate holder, a radiating structure; and conductive offsets arranged to couple the conductive concentric ring structures to the radiating structure.
 2. The apparatus of claim 1, wherein the second conductive plate is grounded.
 3. The apparatus of claim 1, wherein the radiating structure comprises a third conductive plate with a plurality of axisymmetric spiral cutouts.
 4. The apparatus of claim 1, wherein the plasma processing system comprises a processing chamber having a substrate holder, wherein a substrate to be processed in the processing chamber is mounted on the substrate holder.
 5. The apparatus of claim 4, wherein the apparatus is disposed external to the processing chamber.
 6. The apparatus of claim 1, wherein the first conductive plate is coupled to the RF source via a coaxial conductive structure, and wherein the RF source feeds RF power to first conductive plate via the coaxial conductive structure.
 7. The apparatus of claim 1, further comprising non-conductive offsets, the radiating structure coupled to an insulating structure disposed between a conductive inner ring structure of the conductive concentric ring structures and a conductive outer ring structure of the conductive concentric ring structures by the non-conductive offsets.
 8. The apparatus of claim 1, wherein the interface, the radiating structure, and the conductive offsets form a resonant circuit in response to the RF source providing an RF power to the first conductive plate.
 9. An apparatus for a plasma processing system, the apparatus comprising: an interface comprising: a first conductive structure couplable to an RF source, a second conductive structure disposed between the RF source and the first conductive structure, each concentric conductive structure isolated from the second conductive structure by an air gap, and concentric conductive structures; and a radiating structure coupled to the interface.
 10. The apparatus of claim 9, wherein each concentric conductive structure is isolated from an adjacent concentric conductive structure by the air gap.
 11. The apparatus of claim 9, further comprising conductive offsets coupling the concentric conductive structures to the radiating structure.
 12. The apparatus of claim 9, wherein a resonant frequency of the radiating structure is between 5 and 100 megahertz (MHz).
 13. The apparatus of claim 9, wherein the radiating structure comprises: a conductive plate having spiral cutouts; and an inner circular cutout, wherein the first conductive structure is arranged substantially on a same plane as the radiating structure and positioned inside the inner circulator cutout.
 14. The apparatus of claim 9, wherein the plasma processing system comprises a processing chamber having a substrate holder, wherein a substrate to be processed in the processing chamber is mounted on the substrate holder.
 15. An antenna system for exciting plasma by inductive coupling, the antenna system comprising: a plate; a conductive ring structure arranged in parallel to the plate, the plate and the conductive ring structure forming a first capacitor, the capacitance value of the first capacitor being substantially the same along one conductive ring structure; conductive offsets, each conductive offset having a first end and a second end, a first end of each conductive offset coupled to the conductive ring structure in a perpendicular arrangement, each conductive offset arranged equal distance from other conductive offsets along the conductive ring structure; and a plurality of spiral arms coupled to a corresponding second end of each conductive offset, each spiral arm arranged in a radial, azimuthal, and nested arrangement, each spiral arm having the same shape, length, and spacing, the plurality of spiral arms, conductive offsets, and the conductive ring structure forming a resonant structure that resonates at an RF frequency.
 16. The antenna system of claim 15, further comprising at least one drive conductive structure capacitively coupled to the resonant structure and couplable to an RF source.
 17. The antenna system of claim 15, further comprising a conductive coil structure inductively coupled to the resonant structure, the conductive coil structure and the resonant structure forming an inductively coupled pair, and the conductive coil structure being couplable to an RF source.
 18. The antenna system of claim 15, wherein the conductive ring structure comprises a conductive inner ring structure and a conductive outer ring structure adjacent to the conductive inner ring structure, each of the conductive inner ring structure and the conductive outer ring structure being coupled to the plurality of spiral arms by the conductive offsets.
 19. The antenna system of claim 15, wherein one of an inner or an outer edge of each of the plurality of spiral arms is connected to the conductive ring structure by the conductive offsets, and wherein another edge of the each of the plurality of spiral arms not directly connected to a conductive structure or ground.
 20. The antenna system of claim 15, wherein the plurality of spiral arms, the plate, and the conductive ring structure are arranged substantially parallel to each other. 